Reduction sleeve

ABSTRACT

Devices and methods for facilitating insertion of a spinal rod into a rod-receiving channel formed in a bone fixation element are described herein. In some embodiments, a reduction sleeve can include a through-bore sized to receive the bone fixation element and a transverse channel sized to receive the spinal rod and substantially aligned with the rod-receiving channel formed in the bone fixation element. The reduction sleeve can also include at least one break-off point for breaking and removal of the reduction sleeve The reduction sleeve can also include a plurality of threads for engaging a reduction instrument, an alignment mechanism so that the bone fixation element can only be inserted into the reduction sleeve when the rod-receiving channels are aligned, and an inwardly projecting protrusion formed on the inner surface of the reduction sleeve so that, once inserted, the projection contacts a top surface formed on the bone fixation element.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/835,159 filed Aug. 7, 2007, now U.S. Pat. No. 8,663,292, which claimspriority to U.S. provisional patent application Ser. No. 60/839,448,filed Aug. 22, 2006, the contents of which are hereby incorporated byreference in their entireties.

FIELD OF THE INVENTION

The invention relates to a reduction sleeve, more specifically areduction sleeve for facilitating insertion of a longitudinal spinal rodinto a rod-receiving channel formed in a bone fixation element.

BACKGROUND OF THE INVENTION

It is often necessary due to various spinal disorders to surgicallycorrect and stabilize spinal curvatures, or to facilitate spinal fusion.Numerous systems for treating spinal disorders have been disclosed. Oneknown method involves a pair of elongated members, typically spinalrods, longitudinally placed on the posterior spine on either side ofspinous processes of the vertebral column. Each rod is attached tovarious vertebra along the length of the spine by way of vertebraengaging bone fixation elements. The bone fixation elements commonlyinclude a U-shaped rod-receiving channel for receiving the longitudinalspinal rod therein. Moreover, the rod-receiving channel often includesmeans for receiving a set screw or closure cap to subsequent clamp andfix the position of the spinal rod with respect to the bone fixationelement. With this method, the spinal rod(s) may be shaped to maintainthe vertebrae in such an orientation as to correct the spinal disorderat hand (e.g., to straighten a spine having abnormal curvature).Additionally or alternatively, the bone fixation elements may be spacedalong the rods(s) to compress or distract adjacent vertebrae.

Surgeons have, however, often encountered considerable difficulty whenusing this method, due to problems associated with aligning the spinalrod(s) within the rod-receiving channels formed in the heads or bodyportion of the bone fixation elements. For example, the heads of bodyportions of the bone fixation elements may be out of vertical and/orhorizontal alignment with one another due to the curvature of the spineor the size and shape of each vertebrae.

Thus, there exists a need for a surgical instrument and/or apparatus tohelp facilitate insertion of the longitudinal spinal rods into therod-receiving channels formed in the bone fixation elements.

SUMMARY OF THE INVENTION

The present invention is directed to a reduction sleeve for facilitatinginsertion of a spinal rod into a rod-receiving channel formed in a bonefixation element. The reduction sleeve may include a through-bore sizedand configured to receive the bone fixation element and a substantiallytransverse channel sized and configured to receive the spinal rod. Thechannel is preferably substantially aligned with the rod-receivingchannel formed in the bone fixation element so that, once the bonefixation element has been inserted into the reduction sleeve, the spinalrod can pass through the aligned channels. The reduction sleeve may alsoinclude at least one break-off point or region for facilitating breakingand removal of the reduction sleeve once the spinal rod has been securedin the rod-receiving channel of the bone fixation element. The reductionsleeve may also include: (1) a plurality of threads formed thereon forengaging a reduction instrument, (2) an alignment mechanism so that thebone fixation element can only be inserted into the reduction sleevewhen the rod-receiving channels are aligned, and (3) an inwardlyprojecting protrusion formed on the inner surface of the reductionsleeve so that, once inserted, the projection contacts a top surfaceformed on the bone fixation element.

In one exemplary embodiment, the reduction sleeve may include alongitudinal axis, an upper end, a lower end, an outer surface, achannel, and a through-bore extending from the upper end to the lowerend, the through bore defining an inner surface. The through-bore beingsubstantially perpendicular to the longitudinal axis and being sized andconfigured to receive the bone fixation element. The channel beingsubstantially transverse to the longitudinal axis and beingsubstantially aligned with the rod-receiving channel formed in the bonefixation element so that, once the bone fixation element has beeninserted into the reduction sleeve, the spinal rod can pass through thechannel formed in the reduction sleeve and the rod-receiving channelformed in the bone fixation element. The reduction sleeve preferablyfurther including at least one break-off point or region forfacilitating breaking the reduction sleeve into multiple pieces.

In another exemplary embodiment, the reduction sleeve may include alongitudinal axis, an upper end, a lower end, an outer surface, achannel, and a through-bore extending from the upper end to the lowerend, the through-bore defining an inner surface. The through-bore beingpreferably substantially perpendicular to the longitudinal axis andbeing sized and configured to receive the bone fixation element. Thechannel preferably being substantially transverse to the longitudinalaxis and defining a pair of spaced apart arms having a top surface sothat the top surface of the spaced apart arms formed in the reductionsleeve are sized and configured to extend above the top surface formedin the bone fixation element by a distance A, when the bone fixationelement is inserted into the reduction sleeve. The reduction sleevepreferably also including at least one break-off point or region forfacilitating breaking the reduction sleeve into multiple pieces.

In another exemplary embodiment, the reduction sleeve may include alongitudinal axis, an upper end, a lower end having a tapered surfacesized and configured to contact a correspondingly tapered surface formedon a bone fixation element when the bone fixation element is insertedinto the reduction sleeve, an outer surface having a plurality ofthreads formed thereon for engaging a reduction instrument; athrough-bore extending from the upper end to the lower end, thethrough-bore defining an inner surface, the inner surface having aninwardly projecting protrusion formed thereon, and a channel. Thethrough-bore being substantially perpendicular to the longitudinal axisand being sized and configured to receive the bone fixation element. Thechannel being substantially transverse to the longitudinal axis anddefining a pair of spaced apart arms having a top surface. The reductionsleeve may further include at least one break-off point or region forfacilitating breaking the reduction sleeve into multiple pieces. Theinwardly projecting protrusion formed on the inner surface of thereduction sleeve is sized and configured to contact the top surface ofthe bone fixation element, once the bone fixation element has beeninserted into the reduction sleeve, so that the bone fixation elementcan be secured within the reduction sleeve in-between the taperedsurface formed in the lower end of the reduction sleeve and the inwardlyprojecting protrusion.

The reduction sleeve may include a pair of break-off points or regionsformed in the lower end of the reduction sleeve beneath the channelformed in the reduction sleeve. The channel formed in the reductionsleeve may define a pair of spaced apart arms joined by a bridge memberso that the reduction sleeve is generally in the form of a U-shapedmember, the break-off point or region being formed in the bridge member.The break-off point or region may preferably be formed beneath thechannel and extends vertically from the channel to the lower end of thereduction sleeve.

The rod-receiving channel formed in the bone fixation element preferablydefines a pair of spaced apart arms and the channel formed in thereduction sleeve preferably defines a pair of spaced apart arms, thespaced apart arms being substantially aligned with one another once thebone fixation element has been inserted into the reduction sleeve.

The reduction sleeve may further include a plurality of threads forengaging a reduction instrument. The plurality of threads preferablybeing formed on the outer surface of the reduction sleeve.

The lower end of the reduction sleeve preferably includes a taperedsurface sized and configured to receive a correspondingly taperedsurface formed on the bone fixation element.

Preferably, once inserted, the bone anchor extends through the lower endof the reduction sleeve such that the bone anchor may be moveable withrespect to the bone fixation element and with respect to the reductionsleeve.

The reduction sleeve may also include an alignment mechanism so that thebone fixation element can only be inserted into the reduction sleevewhen the rod-receiving channel formed in the bone fixation element isaligned with the channel formed in the reduction sleeve. The alignmentmechanism preferably is sized and configured as an alignment flat formedin the lower end of the reduction sleeve, the alignment flat being sizedand configured to contact a corresponding flat formed on the bonefixation element.

The reduction sleeve may also include a protrusion formed on the innersurface thereof, the protrusion projecting inward from the inner surfaceso that, once inserted, the projection contacts a top surface formed onthe bone fixation element. Once inserted, the bone fixation elementpreferably is secured within the reduction sleeve in-between the lowerend of the reduction sleeve and the protrusion.

The bone anchor is preferably sized and configured to engage a patient'svertebra.

The reduction sleeve of claim preferably has the shape of a sleeve ortubular member.

The transverse channel preferably extends from the upper end towards thelower end.

BRIEF DESCRIPTION OF THE DRAWINGS

The system is explained in even greater detail in the followingexemplary drawings. The drawings are merely exemplary to illustrate thestructure of preferred devices and certain features that may be usedsingularly or in combination with other features. The invention shouldnot be limited to the embodiments shown.

FIG. 1 is a perspective view of a prior art bone fixation element;

FIG. 2 is a cross-sectional view of the prior art bone fixation elementshown in FIG. 1;

FIG. 3 is a perspective view of an exemplary embodiment of a reductionsleeve;

FIG. 4 is a perspective view of a bone fixation element being insertedinto the reduction sleeve of FIG. 3;

FIG. 5 is an alternate exemplary embodiment of a reduction sleeve;

FIG. 6 is a perspective view of the reduction sleeve and bone fixationelement of FIG. 4 being engaged by a screwdriver or other similar typedevice;

FIG. 7 is a perspective view of the reduction sleeve and bone fixationelement of FIG. 4 with a longitudinal spinal rod shown therein;

FIG. 8A is a perspective view of a reduction instrument urging thespinal rod into the reduction sleeve and bone fixation element;

FIG. 8B is another perspective view of the reduction instrument urgingthe spinal rod into the reduction sleeve and bone fixation element;

FIG. 9 is a perspective view of another exemplary embodiment of areduction insertion and screwdriver or other similar type device;

FIG. 10 is a close up, perspective view of the reduction instrument ofFIG. 9 engaging the bone fixation element;

FIG. 11 is another perspective view of the reduction instrument of FIGS.8A-10 incorporating a cap alignment tube;

FIG. 12 is a close up, perspective view of the cap alignment tube ofFIG. 11, engaging the bone fixation element;

FIG. 13 is another perspective view of the reduction instrument;

FIG. 14 is a perspective view of another exemplary embodiment of areduction instrument engaging the set screw or closure cap for urgingthe spinal rod into the reduction sleeve and bone fixation element;

FIG. 15 is a perspective view of the reduction sleeve and bone fixationelement with the spinal rod fully inserted and clamped in the bonefixation element; and

FIG. 16 is a perspective view of the spinal rod fully inserted andclamped in the bone fixation element with the reduction sleeve removed.

DETAILED DESCRIPTION

Certain exemplary embodiments of the invention will now be describedwith reference to the drawings. In general, such embodiments relate to areduction sleeve, by way of non-limiting example, a reduction sleeve foruse in posterior spinal fixation to facilitate insertion of alongitudinal spinal rod in a rod-receiving channel formed in a bonefixation element. The invention may have other applications and uses andshould not be limited to the structure or use described and illustrated.As will be described in greater detail below, the reduction sleeve mayinclude a vertical through-bore sized and configured to receive a bonefixation element and a transverse channel sized and configured toreceive a longitudinal spinal rod. The reduction sleeve may also includea break-off point and/or region so that after the longitudinal spinalrod has been inserted in the rod-receiving channel of the bone fixationelement, the reduction sleeve can be removed from the patient's bodyleaving in place the bone fixation element and spinal rod.

While the reduction sleeve will be described as and may generally beused in the spine (for example, in the lumbar, thoracic or cervicalregions), those skilled in the art will appreciate that the reductionsleeve may be used for fixation of other parts of the body such as, forexample, joints, long bones or bones in the hand, face, feet,extremities, cranium, etc.

As will be described in greater detail below, the reduction sleeve maybe used to facilitate insertion of a longitudinal spinal rod into arod-receiving channel fondled in a bone fixation element. It should beunderstood that the spinal rod may include, but not limited to, a solidrod, a non-solid rod, a flexible or dynamic rod, etc. It should beunderstood that the reduction sleeve is not limited in use to anyparticular type of spinal rod.

As will be described in greater detail below, the reduction sleeve maybe used in conjunction with a bone fixation element in order to assistthe surgeon with insertion of the spinal rod into the rod-receivingchannel formed in the bone fixation element. As generally understood byone of ordinary skill in the art, it should be understood that bonefixation element is used generally and may include, but are not limitedto, poly-axial or mono-axial pedicle screws, hooks (both mono-axial andpoly-axial) including pedicle hooks, transverse process hooks,sublaminar hook, or other fasteners, clamps or implants. One example ofa bone fixation element is the Pangea.™. pedicle screw systemdistributed by Synthes.®. (U.S.A.). As shown in FIGS. 1 and 2, anexemplary embodiment of a bone fixation element 10 is shown. As shown,the bone fixation element 10 may include a bone anchor 12 (shown as abone screw) having an enlarged head portion 14, a body portion 20 (shownas a top loading body portion) having an upper end 22, a lower end 24, arod-receiving channel 26 (shown as a top loading U-shaped rod-receivingchannel) defining a pair of spaced apart aims 28, 30, a sleeve 35 and acollet 36 slidably disposed within the body portion 20, at least aportion of the collet 36 being slidably disposed within the sleeve 35,and a set screw or closure cap 40. In use, the enlarged end portion 14of the bone anchor 12 may be separate from and be disposed within thelower end 24 of the body portion 20 so that the bone anchor 12 canpoly-axial rotate with respect to the body portion 20. Alternatively,the bone anchor or hook 12 may be formed integral with the body portion20 to form a monolithic structure which is sometimes referred to as amono-axial pedicle screw or hook.

Once the spinal rod 45 is inserted into the rod-receiving channel 26,the surgeon can secure the position of the rod 45 with respect to thebody portion 20 and the position of the bone anchor 12 with respect tothe body portion 20 by engaging, for example, by rotating the set screwor closure cap 40. Rotation of the set screw or closure cap 40 may causethe set screw or closure cap 40 to exert a downward force onto thespinal rod 45, which is received within the rod-receiving channel 26,which, in turn, causes the rod 45 to exert a downward force onto thesleeve 35 with causes the sleeve 35 to move with respect to the collet36, which in turn causes the collet 36 to compress around the enlargedhead portion 14 of the bone anchor 12 thereby securing the position ofthe bone anchor 12 with respect to the body portion 20. In addition,rotation of the set screw or closure cap 40 may cause the spinal rod 45to be sandwiched in-between the set screw or closure cap 40 and thesleeve 35 thereby securing the position of the rod 45 with respect tothe body portion 20.

The bone fixation element 10 may be sized and configured with a lowprofile so that the height of the bone fixation element 10 is minimizedin order to reduce the amount of associated trauma. That is, preferably,the overall height of the body portion 20 is minimized so that, onceengaged, the bone fixation element 10 does not extend anymore than isnecessary above the patient's vertebra. The height of the body portionmay be between about 10 mm and 25 mm and, preferably, between about 12mm and 17 mm. It should be understood however that the reduction sleeveis not limited in use to any particular type of bone fixation element.

As shown in FIG. 3, the reduction sleeve 100 may be generally in theshape of a sleeve or tubular member having an upper end 102, a lower end104, an inner surface 105, an outer surface 106 and a longitudinal axis108. The reduction sleeve 100 may also include a through-bore 110extending from the upper end 102 to the lower end 104, the through-bore110 being generally orientated parallel to the longitudinal axis 108 forreceiving a bone fixation element, such as bone fixation element 10, asshown in FIGS. 1 and 2. However, the through-bore can be at an anglewith respect to the longitudinal axis 108 of the reduction sleeve 100.The reduction sleeve 100 may also include a channel 115 that preferablyextends from the upper end 102 towards the lower end 104, the channel115 being generally orientated transverse to the longitudinal axis 108for receiving the longitudinal spinal rod, such as spinal rod 45, asshown in FIGS. 1 and 2. However, the transverse channel can be at anyangle with respect to the longitudinal axis 108 of the reduction sleeve100. The channel 115 defining a pair of spaced apart arms 120, 122 whichmay be joined together in the lower end 104 by a bridge member 124. Inthis manner, the reduction sleeve 100 may be generally in the form of aU-shaped member.

As shown, the reduction sleeve 100 may also include a plurality ofthreads 150 formed on the outer surface 106 of the spaced apart arms120, 122 for threadably engaging a reduction instrument, as will bedescribed in greater detail below. Preferably, the threads 150 begin ator near the upper end 102 and extend substantially the entire length ofthe spaced apart arms 120, 122 and/or the entire length of the channel115. Alternatively, the reduction sleeve 100 may be formed with internalthreads 150 formed on the inner surface 105 of the spaced apart arms120, 122. In addition, it should be understood that other forms ofengagement between the reduction sleeve 100 and reduction instrument arecontemplated, such as, for example, a snap-fit type connection whereinthe spaced apart arms 120, 122 may include a plurality of ridges forengaging a projection formed on the reduction instrument.

As previously described, the bone fixation element 10 may be sized andconfigured with a low profile so that the height of the bone fixationelement 10, and in particular the height of the body portion 20, isminimized in order to reduce the overall amount of associated trauma.One disadvantage of minimizing the height of the bone fixation element10 is that the spinal rod 45 may be vertically and/or horizontallyoffset with respect to the rod-receiving channel 26 formed in the bonefixation element 10 making it more difficult for the surgeon to insertand clamp the spinal rod 45 into the rod-receiving channel 26 of thebone fixation element 10. To this end, incorporation of the reductionsleeve 100 may enable a surgeon to temporary extend the overall heightof the bone fixation element 10 to facilitate insertion of the spinalrod 45 into the rod-receiving channel 26 of the bone fixation element10. Thereafter, once inserted, the reduction sleeve 100 may be removedand/or disposed leaving behind the bone fixation element 10 and clampedspinal rod 45. The reduction sleeve 100 may have a height of about 20 mmto 60 mm and, preferably, between about 28 mm and 35 mm to helpfacilitate insertion of the spinal rod 45 into the rod-receiving channel26 of the bone fixation element 10.

As shown in FIG. 3, the lower end 104 of the reduction sleeve 100 mayinclude a tapered surface 160 for receiving the body portion 20 of thebone fixation element 10 such that, as best shown in FIG. 4, as the bonefixation element 10 is inserted into the through-bore 110 of thereduction sleeve 100, the bone anchor 12 passes through the reductionsleeve 100 so that it may engage the patient's vertebra while the bodyportion 20 of the bone fixation element 10 includes a surface 21,preferably a corresponding tapered lower surface, sized and configuredto be received within the lower end 104 of the reduction sleeve 100. Inthis manner, preferably, the bone anchor 12 may be poly-axially rotatedwith respect to the body portion 20 of the bone fixation element 10 evenafter the bone fixation element 10 is inserted into the reduction sleeve100. Preferably, the tapered surface 160 formed on the lower surface 104of the reduction sleeve 100 and the corresponding tapered surface 21formed on the bone fixation element 10 are sized and configured withintight tolerances to help facilitate retention of the bone fixationelement 10 within the reduction sleeve 100. The tapered surface 21 mayhave a tapered angle of approximately 10 degrees with a height betweenabout 5 mm and about 6 mm.

In use, the rod-receiving channel 26 formed in the body portion 20 ofthe bone fixation element 10 may be sized and configured to align withthe channel 115 formed in the reduction sleeve 100 so that thelongitudinal spinal rod 45 may pass completely through the reductionsleeve 100 and bone fixation element 10 even after the bone fixationelement 10 has been inserted into the reduction sleeve 100. Preferably,the lower end 104 of the reduction sleeve 100 may include an alignmentmechanism so that the bone fixation element 10 can only be inserted intothe reduction sleeve 100 when the rod-receiving channels 26, 115 arealigned. For example, as best shown in FIGS. 3 and 4, the lower end 104of the reduction sleeve 100 may include an alignment flat 175 that maybe sized and configured to engage a corresponding flat 23 formed on thebody portion 20 of the bone fixation element 10. As will be generallyunderstood by one of ordinary skill in the art, other alignmentmechanism may be used, including, for example, one of the reductionsleeve 100 and bone fixation element 10 may include a projection forengaging a groove formed on the other of the reduction sleeve 100 andbone fixation element 10.

As best shown in FIG. 3, the reduction sleeve 100 may also include aledge or protrusion 200 formed and extending inwardly from the innersurface 105 of the spaced apart arms 120, 122. As will be generallyappreciated by one of ordinary skill in the art, during insertion of thebone fixation element 10 into the reduction sleeve 100, the inwardlyprotruding ledge or protrusion 200 will cause the spaced apart arms 28,30 formed on the body portion 20 of the bone fixation element 10 todeflect inwards until the top of the spaced apart arms 28, 30 formed onthe bone fixation element 10 pass completely beyond that inwardlyprotruding ledge or protrusion 200. At that point, the spaced apart arms28, 30 formed on the bone fixation element 10 will revert back to theiroriginal, upright position causing the body portion 20 of the bonefixation element 10 to be secured within the reduction sleeve 100. Moreparticularly, the body portion 20 of the bone fixation element 10 willbe secured between the inwardly protruding ledge or protrusion 200 andthe tapered surface 160 formed at the lower end 104 of the reductionsleeve 100. In this manner, the reduction sleeve 100 and bone fixationelement 10 may be pre-assembled by the manufacturer and/or by thesurgeon prior to insertion so that the reduction sleeve 100 and bonefixation element 10 may be inserted into the patient's vertebra as asingle piece. In addition, as previously described, the tapered surface160 formed on the lower surface 104 of the reduction sleeve 100 and thecorresponding tapered surface 21 formed on the bone fixation element 10are sized and configured within tight tolerances to further secure thebone fixation element 10 within the reduction sleeve 100.

Moreover, as best shown in FIG. 3, the reduction sleeve 100 may alsoinclude one or more break-off point(s) or region(s) 225. Preferably thereduction sleeve 100 includes a pair of break off points or regions 225located on the lower end 104 of the reduction sleeve 100 beneath therod-receiving channel 115. That is, as shown, preferably the break-offpoints or regions 225 are formed beneath the channel 115 and extendvertically from the channel 115 to the lower end 104 of the reductionsleeve 100. In this manner, the break-off points or regions 225 arelocated at the smallest and/or weakness point of the reduction sleeve100 making it easier for the reduction sleeve 100 to be broken, removedand/or discarded.

The break-off points or regions 225 are preferably an area of weaknessformed, preferably intentionally, in the reduction sleeve 100 so thatthe reduction sleeve 100 will break or rupture when subjected to highstresses, such as by intentional stresses induced by the surgeon inorder to break the reduction sleeve 100 into multiple pieces so that thereduction sleeve 100 can be, partially or completely, removed from thepatient's body after the longitudinal spinal rod 45 has been seated andsecured within the rod-receiving channel 26 of the bone fixation element10. The break-off point 225 may be configured as a weakened region, athinned-out area, a groove, etc. As will be appreciated by one ofordinary skill in the art, the reduction sleeve 100 may contain anynumber of break-off points or regions 225 located anyway on thereduction sleeve 100. Incorporation of the break-off points or regions225 enable the reduction sleeve 100 to be discarded. That is, thebreak-off points or regions 225 enable the reduction sleeve 100 to beconstructed as a separate and distinct part from the bone fixationelement 10. This, optionally, enables the reduction sleeve 100 to bemanufactured from a different and/or cheaper material as compared to thebone fixation element 10. Moreover, since the reduction sleeve 100 isbroken and discarded, no sharp edges are left on the bone fixationelement 10, for example, as compared to prior art bone fixation elementsthat incorporate integral extension areas via a break-off point orregion.

Alternatively, as shown in FIG. 5, the reduction sleeve 100 may beconfigured as a side opening or lateral engaging reduction sleeve 100′.In this manner, the reduction sleeve 100′ may be sized and configuredwith a single spaced apart arm 120′ for engaging a reduction instrument,as will be described in greater detail below. In this embodiment, thebreak-off point 225 may be omitted as the reduction sleeve 100′ may bepreferably sized and configured to engage the bone fixation element 10from a single side thereof, thus enabling the surgeon to engage anddisengage the reduction sleeve 100′ as necessary. One particularadvantage of this embodiment is that the reduction sleeve 100′ is notbroken and/or discarded after each use but rather may be reused againduring the surgery.

Referring again to FIG. 4, in use, the bone fixation element 10 may beinserted into the reduction sleeve 100 via the through-bore 110 so thatpreferably the body portion 20 of the bone fixation element 10 is seatedbetween the tapered surface 160 of the lower end 104 of the reductionsleeve 100 and the inwardly projecting ledge or protrusion 200 formed onthe spaced apart arms 120, 122. The bone anchor 12 extending through thelower end 104 of the reduction sleeve 100 and preferably being capableof poly-axially rotating with respect to the bone fixation element 10and reduction sleeve 100. Moreover, preferably the rod-receiving channel26 formed in the bone fixation element 10 may be aligned with therod-receiving channel 115 formed in the reduction sleeve 100 so that thelongitudinal spinal rod 45 is able to pass completely through theassembled device 250 (e.g., the reduction sleeve 100 with the bonefixation element 10 seated therein).

As best shown in FIG. 6, with the bone fixation element 10 securedbetween the inner surface 105 of the reduction sleeve 100 and theinwardly projecting ledge or protrusion 200, the assembled device 250may be secured to a patient's body, preferably the patient's vertebra,by a screwdriver or other similar type device 300. Once engaged to thepatient's vertebra, the surgeon can preferably, so long as a mono-axialbone fixation element isn't used, poly-axially rotate the body portion20 of the bone fixation element 10 and the reduction sleeve 100 withrespect to the bone anchor 12 so that the longiditudinal spinal rod 45can be inserted into the rod-receiving channel 115 of the reductionsleeve 100. At this point, the spinal rod 45 may or may not be seatedwithin the rod-receiving channel 26 of the bone fixation element 10, asbest shown in FIG. 7.

Next, as best shown in FIGS. 8A and 8B, a reduction instrument 310 maybe used to engage the reduction sleeve 100 in order to urge the spinalrod 45 into the rod-receiving channel 26 of the bone fixation element10. The reduction instrument 310 may include a tube 311 having a distalend 312 and a proximal end 314, the distal end 312 may include one ormore internal threads 316 for engaging the external threads 150 formedon the spaced apart aims 120, 122 of the reduction sleeve 100 such thatrotation of the reduction instrument 310 causes the reduction instrument310 to move with respect to the reduction sleeve 100, which in turn, maycause the distal end 312 of the reduction instrument 310 to contact thespinal rod 45 so that continued rotation of the reduction instrument 310urges the rod 45 into the rod-receiving channel 26 of the bone fixationelement 100. That is, rotation of the reduction instrument 310 causesthe reduction instrument 310 to move with respect to the reductionsleeve 100, which, in turn, causes the distal end 312 of the reductioninstrument 310 to contact the spinal rod 45 so that continued rotationof the reduction instrument 310 moves the rod 45 from a first positionwhere the rod 45 may be in the channel 115 formed in the reductionsleeve 100 but not in the rod-receiving channel 26 of the bone fixationelement 100, as shown in FIG. 8A, to a second position where the rod 45may be located in both the channel 115 formed in the reduction sleeve100 and the rod-receiving channel 26 of the bone fixation element 100,as shown in FIG. 8B. Alternatively, as previously described, thereduction instrument 310 may include external threads for engaginginternal threads formed on the spaced apart arms 120, 122 of thereduction sleeve 100 or any other attachment means known in the art. Thereduction sleeve 100 and reduction instrument 310 are preferablyconfigured with corresponding increased thread pitch to enable fasterreduction of the spinal rod 45. That is, the reduction sleeve 100 andreduction instrument 310 may be configured with corresponding increasedthread pitch so that less rotation of the reduction instrument 310 isrequired to move the reduction instrument 310 axially with respect tothe reduction sleeve 100. For example, the reduction sleeve 100 andreduction instrument 310 may be configured with an M15 thread pitch.However, as will be appreciated by one of ordinary skill in the art, anythread pitch may be used. In addition, as shown, the reductioninstrument 310 may also include a handle 318, preferably a T-handle, tofacilitate rotation of the reduction instrument 310.

Moreover, as best shown in FIGS. 9 and 10, the reduction instrument 310(shown here with an optionally knurled knob 318′ as opposed to theT-handle 318 mentioned above) preferably includes a central bore 320extending from the proximal end 314 to the distal end 312. The bore 320preferably being sized and configured to receive the set screw orclosure cap 40 and associated screwdriver or similar type device 330 sothat once the spinal 45 has been urged into the rod-receiving channel 26formed in the bone fixation element 10, the surgeon can clamp the spinalrod 45 within the rod-receiving channel 26 of the bone fixation element10 by securing the set screw or closure cap 40 to the bone fixationelement 10. As will be generally understood by one or ordinary skill inthe art, the knurled knob 318′ and T-handle 318 are easilyinterchangeable.

In addition, as best shown in FIGS. 11 and 12, the central bore 320 maybe sized and configured to receive an optional cap alignment tube 340.The cap alignment tube 340 may be preferably sized and configured withan alignment mechanism so that when the cap alignment tube 340 isinserted into the reduction instrument 310, the cap alignment tube 340only permits the set screw or closure cap 40 to be inserted into thespaced apart arms 120, 122 formed on the bone fixation element 10 inproper alignment. More particularly, as shown in FIG. 12, the capalignment tool 340 may include a plurality of slots 345 extending from adistal end 344 thereof. The slots 345 being sized and figured to receiveand guide tabs 41 (as best shown in FIG. 1) extending from the set screwor closure cap 40 into engagement with the spaced apart arms 28, 30formed on the bone fixation element 10. In addition, the cap alignmenttube 340 may be preferably sized and configured to prevent the tabs 41formed on the set screw or closure cap 40 from accidentally beingdropped into the rod-receiving channel 26 formed on the bone fixationelement 10. The cap alignment tool 340 may also incorporate a handle(not shown). Preferably the cap alignment tool 340 includes a handleextending from the proximal end 342 thereof.

As shown in FIG. 13, the reduction instrument 310 may also include aviewing window 325 formed in a side of the tube 311 to enable thesurgeon to see the top of the reduction sleeve 100 and bone fixationelement 10. In addition, the reduction instrument 310 may also includean indicator 327, more preferably an indicator line, to preciselyindicate to the surgeon when the spinal rod 45 has been fully insertedinto the rod-receiving channel 26 formed in the bone fixation element 10to prevent over or under rotation.

Alternatively, as best shown in FIG. 14, the distal end 312 of thereduction instrument 310 may be sized and configured to receive and/orengage the set screw or closure cap 40 so that the set screw or closurecap 40 contacts and urges the spinal rod 45 into the rod-receivingchannel 26 formed on the bone fixation element 10. Thus, eliminating theneed for the separate set screw of closure cap screwdriver 330. Itshould be further noted that as shown in this exemplary embodiment, thereduction sleeve 100 has internal threads for engaging external threadsformed on the reduction instrument 310. Alternatively, however, thereduction sleeve 100 could have external threads for engaging internalthreads formed on the reduction instrument 310.

As best shown in FIG. 15, once the spinal rod 45 has been secured withinthe rod-receiving channel 26 of the bone fixation element 10, thereduction instrument 310 may be removed. Next the reduction sleeve 100may be removed by breaking the reduction sleeve 100 into multiple piecesat the break-off point 225 leaving the engaged bone fixation element 10and clamped spinal rod 45, as shown in FIG. 16.

The reduction sleeve may be manufactured from any biocompatible materialknown in the art. The reduction sleeve may be manufactured from the samematerial as the bone fixation element or from a different material. Thereduction sleeve may be manufactured from, but not limited to, titanium,titanium alloys, stainless steel, cobalt chromium, fibers, polymers,plastics, etc. Moreover, as will be generally understood by one ofordinary skill in the art, the reduction sleeve 100 may be provided inany number of sizes and configurations depending on the size andconfiguration of the bone fixation elements and spinal rods being used,which may be dependent on the type and location of the surgery beingperformed.

As will be appreciated by those skilled in the art, any or all of thecomponents described herein such as, for example, the reduction sleeve,spinal rod, bone fixation elements, instruments, etc. may be provided insets or kits so that the surgeon may select various combinations ofcomponents to perform a fixation procedure and create a fixation systemwhich is configured specifically for the particular needs/anatomy of apatient. It should be noted that one or more of each component may beprovided in a kit or set. In some kits or sets, the same device may beprovided in different shapes and/or sizes (e.g., reduction sleeves ofdifferent sizes).

While the foregoing description and drawings represent the preferredembodiments of the present invention, it will be understood that variousadditions, modifications, combinations and/or substitutions may be madetherein without departing from the spirit and scope of the presentinvention as defined in the accompanying claims. In particular, it willbe clear to those skilled in the art that the present invention may beembodied in other specific forms, structures, arrangements, proportions,and with other elements, materials, and components, without departingfrom the spirit or essential characteristics thereof. One skilled in theart will appreciate that the invention may be used with manymodifications of structure, arrangement, proportions, materials, andcomponents and otherwise, used in the practice of the invention, whichare particularly adapted to specific environments and operativerequirements without departing from the principles of the presentinvention. In addition, features described herein may be used singularlyor in combination with other features. The presently disclosedembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims, and not limited to the foregoingdescription.

The invention claimed is:
 1. A spinal rod reduction system, comprising:a bone fixation element including: a bone anchor having a head portionand a shank portion extending distally from the head portion; and areceiver having a base, in which the head portion of the bone anchor isseated, with first and second arms extending proximally therefrom, thefirst and second arms defining a rod-receiving channel therebetween forreceiving a spinal rod; and a reduction sleeve comprising: alongitudinal axis, an upper end, a lower end in which a lower opening isformed, an outer surface, a channel, and a through-bore extending fromthe upper end to the lower end, the through bore defining an innersurface; wherein the lower opening is sized such that the receiver ofthe bone fixation element cannot fit through the lower opening and suchthat a distal-facing end surface of the distal-most end of the receiverof the bone fixation element abuts a proximal-facing surface of thelower end of the reduction sleeve when the bone fixation element isinserted through the reduction sleeve; wherein the through-bore issubstantially parallel to the longitudinal axis and the through-bore issized and configured to receive the bone fixation element; and whereinthe channel is substantially transverse to the longitudinal axis and thechannel is substantially aligned with the rod-receiving channel formedin the bone fixation element so that, once the bone fixation element hasbeen inserted into the reduction sleeve, the spinal rod can pass throughthe channel formed in the reduction sleeve and the rod-receiving channelformed in the bone fixation element.
 2. The system of claim 1, whereinthe reduction sleeve includes a pair of break-off points or regionsformed in the lower end of the reduction sleeve beneath the channelformed in the reduction sleeve.
 3. The system of claim 1, wherein thechannel formed in the reduction sleeve defines a pair of spaced apartarms joined by a bridge member so that the reduction sleeve is generallyin the form of a U-shaped member, and wherein the reduction sleeveincludes at least one break-off point or region being formed in thebridge member.
 4. The system of claim 1, wherein the reduction sleeveincludes at least one break-off point or region formed beneath thechannel and extending vertically from the channel to the lower end ofthe reduction sleeve.
 5. The system of claim 1, wherein the first andsecond arms of the bone fixation element are substantially aligned witha pair of spaced apart arms defined by the channel of the reductionsleeve once the bone fixation element has been inserted into thereduction sleeve.
 6. The system of claim 1, wherein the reduction sleevefurther comprises a plurality of threads for engaging a reductioninstrument.
 7. The system of claim 6, wherein the plurality of threadsare formed on the outer surface of the reduction sleeve.
 8. A spinal rodreduction system, comprising: a bone fixation element including: a boneanchor having an elongate shank, an enlarged head portion, and areceiver having a rod-receiving channel formed therein for receiving aspinal rod, the rod-receiving channel defining a pair of spaced apartarms having a top surface; and the enlarged head portion is polyaxiallyseated in the reciever; and a reduction sleeve comprising: alongitudinal axis, an upper end, a lower end, an outer surface, achannel, and a through-bore extending from the upper end to the lowerend, the through-bore defining an inner surface; wherein the innersurface includes a tapered surface at the lower end of the reductionsleeve configured to engage a corresponding tapered distal-facing endsurface of the receiver of the bone fixation element to retain thereceiver wholly within the reduction sleeve; wherein the through-bore issubstantially parallel to the longitudinal axis and the through-bore issized and configured to receive the bone fixation element; wherein thechannel is substantially transverse to the longitudinal axis and thechannel defines a pair of spaced apart arms having a top surface; andwherein the top surfaces of the spaced apart arms formed in thereduction sleeve are sized and configured to extend above the topsurfaces formed in the bone fixation element by a distance A, when thebone fixation element is inserted into the reduction sleeve.
 9. Thesystem of claim 8, wherein the spaced apart arms formed in the reductionsleeve are sized and configured to substantially align with the pair ofspaced apart arms formed in the bone fixation element, when the bonefixation element is inserted into the reduction sleeve, so that thechannel formed in the reduction sleeve is substantially aligned with therod-receiving channel formed in the bone fixation element so that thespinal rod can pass through the channel and the rod-receiving channelwhen the bone fixation element is inserted into the reduction sleeve.10. The system of claim 8, wherein the distance A is at least 20 mm. 11.The system of claim 8, wherein the reduction sleeve includes a pair ofbreak-off points or regions formed in the lower end of the reductionsleeve beneath the channel formed in the sleeve.
 12. The system of claim8, wherein the pair of spaced apart arms formed in the sleeve are joinedby a bridge member, and wherein the reduction sleeve includes at leastone break-off point or region formed in the bridge member.
 13. Thesystem of claim 8, wherein the reduction sleeve includes at least onebreak-off point or region formed beneath the channel and extendingvertically from the channel to the lower end of the reduction sleeve.14. The system of claim 8, wherein the reduction sleeve furthercomprises a plurality of threads for engaging a reduction instrument.15. A reduction sleeve system for facilitating insertion of alongitudinal spinal rod into a bone fixation element, comprising: a bonefixation element including a bone anchor having a head portionpolyaxially disposed in a receiver, the receiver having a rod-receivingchannel formed therein for receiving a spinal rod, the rod-receivingchannel defining a pair of spaced apart arms having a top surface, areduction sleeve comprising: a longitudinal axis; an upper end; a lowerend having a tapered surface sized and configured to contact acorrespondingly tapered surface formed on the distal most end of thereceiver of the bone fixation element when the bone fixation element isinserted into the reduction sleeve; an outer surface having a pluralityof threads formed thereon for engaging a reduction instrument; athrough-bore extending from the upper end to the lower end, thethrough-bore defining an inner surface, the inner surface having aninwardly projecting protrusion formed thereon; and a channel; wherein alower opening formed in the tapered surface of the lower end is sizedsmaller than the receiver of the bone fixation element such that thereceiver cannot pass through the lower opening; wherein the through-boreis substantially parallel to the longitudinal axis and the through-boreis sized and configured to receive the bone fixation element; andwherein the channel is substantially transverse to the longitudinal axisand the channel defines a pair of spaced apart arms having a topsurface; and wherein the reduction sleeve further comprises at least onebreak-off point or region for facilitating breaking the reduction sleeveinto multiple pieces; and wherein the inwardly projecting protrusionformed on the inner surface of the reduction sleeve is sized andconfigured to contact the top surface of the receiver of the bonefixation element, once the bone fixation element has been inserted intothe reduction sleeve, so that the receiver of the bone fixation elementcan be secured within the reduction sleeve in-between the taperedsurface formed in the lower end of the reduction sleeve and the inwardlyprojecting protrusion.
 16. The reduction sleeve system of claim 15,wherein the spaced apart arms formed in the reduction sleeve are sizedand configured to substantially align with the pair of spaced apart armsformed in the bone fixation element, when the bone fixation element isinserted into the reduction sleeve, so that the channel formed in thereduction sleeve is substantially aligned with the rod-receiving channelformed in the bone fixation element so that the spinal rod can passthrough the channel and the rod-receiving channel when the bone fixationelement is inserted into the reduction sleeve.
 17. The reduction sleevesystem of claim 15, wherein the reduction sleeve includes a pair ofbreak off points or regions formed in the lower end of the reductionsleeve beneath the channel formed in the sleeve.
 18. The reductionsleeve system of claim 15, wherein the pair of spaced apart arms formedin the sleeve are joined by a bridge member, the break-off point orregion being formed in the bridge member.
 19. The reduction sleevesystem of claim 15, wherein the break-off point or region is formedbeneath the channel and extends vertically from the channel to the lowerend of the reduction sleeve.
 20. The reduction sleeve system of claim15, wherein the reduction sleeve includes an alignment mechanism so thatthe bone fixation element can only be inserted into the reduction sleevewhen the rod-receiving channel formed in the bone fixation element isaligned with the channel formed in the reduction sleeve.